I've enabled[0] FB_NVIDIA and during normal booting the screen flickers after the "... : fixmap" message and the screen clears and is filled again from the top - maybe the messages would've been there if booted w/o the framebuffer enabled.

Right now I'm happy that Ben's fix helped to get past this message, but the system remains unsuable[1] with the latest -git, but more debugging has to wait until tomorrow...